package com.twenty.seven.toolbox.encrypt.symmetry;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * @Author 001
 * @Date 2020/1/7 9:56
 * @TODO DES算法对称加密和解密，可以key值要自己定
 **/
public class DESUtil {
    /**
     * DES 算法
     */
    private static final String KEY_ALGORITHM = "DES";
    /**
     *     默认加密算法
     */
    private static final String DEFAULT_CIPHER_ALGORITHM = "DES/ECB/PKCS5Padding";

    /**
     * DES 加密操作
     * @param content 加密内容
     * @param key 加密密钥
     * @return 返回Base64转码后的加密数据
     */
    public static String encrypt(String content,String key) throws Exception{
        // 创建密码器
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
        //编码
        byte[] byteContent = content.getBytes("utf-8");
        // 初始化为加密模式的密码器
        cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));
        // 加密
        byte[] result = cipher.doFinal(byteContent);
        //通过Base64转码返回
        return Base64.encodeBase64String(result);
    }

    /**
     * DES解密
     * @param content
     * @param key
     * @return
     */
    public static String decrypt(String content,String key) throws Exception{
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE,getSecretKey(key));
        byte[] result = cipher.doFinal(Base64.decodeBase64(content));
        return new String(result,"utf-8");
    }

    /**
     * 生成加密密钥
     * @param key key值
     * @return
     */
    private static SecretKeySpec getSecretKey(final String key) throws NoSuchAlgorithmException {
        KeyGenerator kg = null;
        kg = KeyGenerator.getInstance(KEY_ALGORITHM);
        //DES要求密钥长度56
        kg.init(56,new SecureRandom(key.getBytes()));
        SecretKey secretKey = kg.generateKey();
        //转化为DES专用密钥
        return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);
    }

    public static void main(String[] args) throws Exception{
        String content = "wangzhq,您好!";
        String key = "mgQt5lsxFby5uN/Ai5GPQA==";
        System.out.println("Content:"+content);
        String s1 = DESUtil.encrypt(content,key);
        System.out.println("S1:"+s1);
        System.out.println("S2;"+DESUtil.decrypt(s1,key));
    }
}
